1. Field of the Invention
This invention relates to an eye-tracking method, more particularly to an eye-tracking method that is non-invasive.
2. Description of the Related Art
In a conventional eye tracking technology, a contact lens mounted thereon with an inductance coil is worn by a user. When the user moves his/her eye, which in turn moves the inductance coil, a change in a magnetic flux occurs, whereby an electromotive force is generated from which an orientation of the eye of the user is determined. The contact lens, however, when worn by the user, irritates the eye of the user. Furthermore, since the contact lens has two layers, the contact lens, when worn by the user, impairs the vision of the user.
In another conventional eye tracking technology, electrodes are attached to a periphery of the eye of the user through which a voltage may be detected. When the user moves his/her eye, a change in the detected voltage occurs, whereby an orientation of the eye of the user is determined. The electrodes, however, when attached to the periphery of the eye of the user, causes discomfort to the user. Moreover, since secretions from the skin of the user have an affect upon the detected voltage, the orientation of the eye determined in this conventional technology is therefore inaccurate. Further, a relatively small voltage change is not detectable by this conventional technology.
In order to solve the above-mentioned problems, non-invasive eye-tracking technologies have been proposed. In one of the non-invasive eye-tracking technologies, the user wears a pair of eyeglasses, or a helmet, mounted thereon with a camera. The user, however, is required to maintain the position of the camera relative to the eye while using this conventional technology. This causes inconvenience on the part of the user. In another non-invasive eye-tracking technology, in which two charged-coupled device (CCD) cameras are used and complicated calculations are involved, high software and hardware implementation costs are incurred.